Custom police vans. One for prisoners, one for the chief. Instructions on YouTube and Bricksburgh.com.
For tutorial go to :
http://www.youtube.com/watch?v=_QzQ4kJ849c&feature=share&list=UUgghjALEm85p0A8_iQw8wrA

These vans are really nice! They would be a nice addition to any police force! I am a big fan of yours guys creations! I have built your flatbed truck and the sports car from spare parts and they both are great!